ParallelTaskDistributor Class Reference

#include <xmipp_threads.h>

Inheritance diagram for ParallelTaskDistributor:

Public Member Functions
	ParallelTaskDistributor (size_t nTasks, size_t bSize)
virtual	~ParallelTaskDistributor ()
void	clear ()
void	setBlockSize (size_t bSize)
int	getBlockSize () const
bool	getTasks (size_t &first, size_t &last)
bool	setAssignedTasks (size_t tasks)

Public Attributes
size_t	numberOfTasks

Protected Member Functions
virtual void	lock ()=0
virtual void	unlock ()=0
virtual bool	distribute (size_t &first, size_t &last)=0

Protected Attributes
size_t	blockSize
size_t	assignedTasks

Detailed Description

This class distributes dynamically N tasks between parallel workers.

This class is a generalization of a common task in a parallel environment of dynamically distribute N tasks between workers(threads or mpi process). Each worker will ask for a group of tasks, process it and ask for more tasks until there is not more task to process.

This class is abstract and only serves as base for concrete implementations, which will provides the specific lock mechanisms and the way of distribution.

Definition at line 366 of file xmipp_threads.h.

Constructor & Destructor Documentation

ParallelTaskDistributor()

ParallelTaskDistributor::ParallelTaskDistributor	(	size_t	nTasks,
		size_t	bSize
	)

Constructor. The number of jobs and block size should be provided.Constructor for Master node.

Definition at line 289 of file xmipp_threads.cpp.

{
    if (!(nTasks && bSize && bSize <= nTasks))
        REPORT_ERROR(ERR_ARG_INCORRECT, "nTasks and bSize should be > 0, also bSize <= nTasks");

    numberOfTasks = nTasks;
    blockSize = bSize;
    assignedTasks = 0;
}

~ParallelTaskDistributor()

virtual ParallelTaskDistributor::~ParallelTaskDistributor ( )

inlinevirtual

Destructor.

Definition at line 386 of file xmipp_threads.h.

    {}

Member Function Documentation

clear()

void ParallelTaskDistributor::clear

(

)

Restart the number of assigned tasks and distribution again. This method should only be called in the main thread before start distributing the tasks between the workers threads.

Definition at line 299 of file xmipp_threads.cpp.

{
    lock();
    assignedTasks = 0;
    unlock();
}

distribute()

virtual bool ParallelTaskDistributor::distribute ( size_t &  first, size_t &  last  )

protectedpure virtual

Implemented in ThreadTaskDistributor, and MpiTaskDistributor.

getBlockSize()

int ParallelTaskDistributor::getBlockSize

(

)

const

Return the number of tasks assigned in each request

Definition at line 313 of file xmipp_threads.cpp.

{
    return blockSize;
}

getTasks()

bool ParallelTaskDistributor::getTasks	(	size_t &	first,
		size_t &	last
	)

Gets parallel tasks.

This function will be called by workers for asking tasks until there are not more tasks to process. Example:

//...
ParallelTaskDistributor * td = new ThreadTaskDistributor(1000, 100);
//...
//function to perform some operation
//to N images executed in parellel
void processSeveralImages()
{
    size_t firstImage, lastImage;
    while (td->getTasks(firstImage, lastImage))
        for (size_t image = firstImage; image <= lastImage; ++image)
        {
            //...
            processOneImage(image);
            //...
        }
}

Definition at line 318 of file xmipp_threads.cpp.

{
    lock();
    bool result = distribute(first, last);
    unlock();
    return result;
}

lock()

virtual void ParallelTaskDistributor::lock ( )

protectedpure virtual

Implemented in ThreadTaskDistributor.

setAssignedTasks()

bool ParallelTaskDistributor::setAssignedTasks

(

size_t

tasks

)

Definition at line 326 of file xmipp_threads.cpp.

{
    if (tasks < 0 || tasks >= numberOfTasks)
        return false;
    lock();
    assignedTasks = tasks;
    unlock();
    return true;
}

setBlockSize()

void ParallelTaskDistributor::setBlockSize

(

size_t

bSize

)

Set the number of tasks assigned in each request

Definition at line 306 of file xmipp_threads.cpp.

{
    lock();
    blockSize = bSize;
    unlock();
}

unlock()

virtual void ParallelTaskDistributor::unlock ( )

protectedpure virtual

Implemented in ThreadTaskDistributor.

Member Data Documentation

assignedTasks

size_t ParallelTaskDistributor::assignedTasks

protected

Definition at line 372 of file xmipp_threads.h.

blockSize

size_t ParallelTaskDistributor::blockSize

protected

Definition at line 370 of file xmipp_threads.h.

numberOfTasks

size_t ParallelTaskDistributor::numberOfTasks

Definition at line 376 of file xmipp_threads.h.

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The documentation for this class was generated from the following files:

• xmippCore/core/xmipp_threads.h
• xmippCore/core/xmipp_threads.cpp